A Hybrid DFT Description of the Ground State Properties of Americium-I

Raymond Atta-Fynn; Asok K. Ray

A Hybrid DFT Description of the Ground State Properties of Americium-I

POSTER

Abstract

Americium-I (Am-I) is a strongly correlated metal which has been determined experimentally to be a non-magnetic, double HCP crystal with well-localized 5$f$ electrons. However, theoretical descriptions of Am-I based on density functional theory (DFT) yield the correct structural properties but the wrong magnetic ground state and a very poorly described 5$f$ electron spectra. In this work, we will show that hybrid DFT, which replaces a fraction (40{\%} to be exact) of approximate DFT exchange with exact Hartree-Fock (HF) exchange, yields structural, magnetic, and electronic properties of Am-I which are in excellent agreement with experimental data. The primary reason why DFT fails to describe Am-I, namely the overestimation of the exchange interaction leading to a spin-polarized ground state, and how this failure is corrected by hybrid DFT, will be discussed.

Authors

Raymond Atta-Fynn

Physics Department, The University of Texas at Arlington, Physics Department, University of Texas at Arlington, Texas 76019
Asok K. Ray

Physics Department, The University of Texas at Arlington, Physics Department, University of Texas at Arlington, Texas 76019, Physics Department, University of Texas at Arlington, TX 76019, Department of Physics, University of Texas Arlington